A Marquette Law School poll released earlier this week produced a similar result, with Romney holding an 8 percent lead over Santorum.

The Wisconsin primary is critical for the Santorum campaign on a number of fronts.

There are 42 delegates at stake in the winner-take-all contest, and Romney is likely to sweep next Tuesday’s other primaries in Maryland and in Washington, D.C., where Santorum failed to make the ballot.

With Romney already holding a more than two-to-one lead in delegates, and leading by double digits in most national polls, Santorum needs to mount a momentous comeback if he hopes to undermine the narrative that Romney is the party’s inevitable nominee.

A victory for Santorum in Wisconsin would be a good start, as the former Pennsylvania senator has touted his ability to connect with blue-collar voters.

However, Santorum has so far been unable to close the deal in the Midwest, falling just short of Romney in Michigan and Ohio, with Wisconsin appearing to be lining up similarly.

Santorum once again leads among those who identify as “very conservative,” Tea Party supporters and evangelicals, but has been unable to make a dent in Romney’s support from liberal and centrist Republicans or wealthy voters.

The poll also found that the eventual GOP nominee will have his work cut out for him against Obama in Wisconsin this fall — the president leads Romney 52 percent to 35, and leads Santorum 51 percent to 38.

The poll was conducted from March 26 to 27 and has a 2 percent margin of error.